In yet another compelling reason to beef up border security, a new federal court case outlines how Mexican drug cartels have teamed up with violent street gangs to operate inside the United States.

The case involves dozens of members of the Barrio Azteca gang charged with operating a massive drug-trafficking and money-laundering enterprise. A handful of members have already been convicted and were sentenced in Texas this week, while others face trial next spring for racketeering, murder, drug offenses, money laundering and obstruction of justice.

Information released by the Department of Justice (DOJ) this week says Barrio Azteca is also responsible for the March 2010 murders in Juarez of a U.S. Consulate employee, her husband and another associate. Details of the gang’s vast operations in Mexico and the U.S. illustrate how violence has gone well beyond the southern border despite assurances from Homeland Security officials that the region is safer than ever.

According to the DOJ documents members and associates of the Barrio Azteca have engaged in a host of criminal activity since 2003, including drug trafficking, extortion, money laundering, kidnapping and murder. The gang makes money by importing heroin, cocaine and marijuana into the United States from Mexico, according to the DOJ. Some of the profits are used to help incarcerated gang members pay for defense lawyers or fines while a chunk of it is used to buy more drugs, guns and ammunition.

This is a sophisticated enterprise operating on American soil with money from Mexican drug proceeds. The DOJ says the gang has a militaristic command structure and includes captains, lieutenants, sergeants, soldiers and associates – all with the purpose of maintaining power and enriching its members and associates through drug trafficking, money laundering, extortion, intimidation, violence, threats of violence and murder.

These sorts of gangs have been working in the U.S. for years, according to various federal reports that have provided alarming statistics about the criminal enterprises. As far back as 2008, the DOJ’s National Drug Intelligence Center revealed how Mexican drug trafficking organizations represent the greatest crime threat in the U.S. Two years later, a separate report said Mexican drug cartels have expanded into every region of the country, including idyllic rural areas.

A few months ago Texas state authorities published yet another report documenting how Mexican drug cartels have transformed parts of the state into a war zone where shootings, beheadings, kidnappings and murders are common. It further revealed that drug-cartel violence is so severe that Texas counties along the Mexican border are under attack around the clock.